U.S. patent number 6,350,126 [Application Number 09/654,155] was granted by the patent office on 2002-02-26 for bone implant.
Invention is credited to Ricardo Levisman.
United States Patent |
6,350,126 |
Levisman |
February 26, 2002 |
Bone implant
Abstract
A bone implant for fixing a fixing stud of a dental prosthesis
into a bone, the implant being a non-expandable or an expandable
implant comprising a tubular body and an intermediate mounting
member removably mounted into the body, the intermediate member
receiving the fixing stud and being capable of being removed from
the body even after a long time of the implantation of the implant,
thus permitting the removal of the stud from the implant in the
event the stud is broken within the implant.
Inventors: |
Levisman; Ricardo (1425 Cuidad
de Buenos Aires, AR) |
Family
ID: |
24623656 |
Appl.
No.: |
09/654,155 |
Filed: |
September 1, 2000 |
Current U.S.
Class: |
433/173; 433/1;
433/174 |
Current CPC
Class: |
A61C
8/0033 (20130101) |
Current International
Class: |
A61C
8/00 (20060101); A61C 008/00 () |
Field of
Search: |
;433/172,173,174 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Cranin, Norman, Atlas of Oral Implantology, 2.sup.nd Ed., St.
Louis, Mosby, 1999, pp. 326 and 343..
|
Primary Examiner: O'Connor; Cary E.
Attorney, Agent or Firm: Greer, Burns & Crain, Ltd.
Claims
I claim:
1. A bone implant comprising a fixing tubular body for fixing in
the bone, the tubular body including a distal end for being affixed
within a bone bore and a proximal end for remaining accessible
outside the bone and a prosthesis piece being received in the
proximal end, the bone implant comprising:
a mounting intermediate member for mounting said prosthesis piece,
the intermediate member being rotatably removably mounted within
said tubular body;
the intermediate member including a proximal end having a coupling
plate abutting directly said proximal end of the tubular body and
an inner surface for receiving a fixing stud of said prosthesis
piece; and
the coupling plate of the intermediate member including means for
connecting a tool for easily removing the intermediate member from
the tubular body.
2. The bone implant of claim 1, wherein said intermediate member is
at least partially threadably fixed into the tubular body.
3. The bone implant of claim 2, wherein said intermediate member
defines at its proximal end a plate or head having a polygonal
configuration.
4. The bone implant of claim 1, wherein said intermediate member is
rotatably attached within the tubular body, said inner surface of
the intermediate member being threaded and receives a fixing stem
having a proximal end threaded in said threaded inner surface and a
distal end having a retention head arranged in said distal end of
the tubular body.
5. The bone implant of claim 4, wherein the implant is an
expandable implant and the distal end of the tubular body includes
a plurality of longitudinal cuts defining an expandable portion
that is capable of being radially outwardly expanded by said
retention head longitudinally moving along the tubular body, said
retention head defining an expanding member fixed at the distal end
of the fixing stem and retained against rotation in said distal end
of the tubular body but permitted to slide within said tubular
body.
6. The bone implant of claim 5, wherein the expanding member has a
truncate pyramid shape with its vertexes in said longitudinal cuts
of the tubular body.
7. The bone implant of claim 5, wherein the inner surface of the
intermediate member is smooth and receives said fixing stud of the
prosthesis piece, the stud being smooth and is fixed within the
intermediate member by adhesive cement.
8. The bone implant of claim 5, wherein the fixing tubular body has
an outer smooth surface treated to enhance its adherence
characteristics.
9. The bone implant of claim 1, wherein said inner surface of the
intermediate member is at least partially threaded and threadably
receives said fixing stud that is at least partially threaded.
10. The bone implant of claim 1, wherein said proximal end of the
fixing tubular body and said proximal end of the intermediate
member have corresponding coupling plates with one plate abutted
against the other.
11. The bone implant of claim 10, wherein the plate of the
intermediate mounting member includes a radially extended notch for
receiving a screwdriver for rotating the intermediate member, said
notch passing through the plate of the intermediate member.
12. The bone implant of claim 11, wherein the plate at the proximal
end of the tubular body includes a radial groove for receiving said
screwdriver, said groove and said notch being capable of being
positioned in a mating relationship.
13. The bone implant of claim 1, wherein the tubular body has an
outer surface provided with threads.
14. The bone implant of claim 1, wherein the inner surface of the
intermediate member and the stud are partially threaded and
partially smooth.
15. The bone implant of claim 1, wherein the outer surface of the
intermediate member and the bore of the tubular body have a
threaded portion and a smooth portion engaged together.
16. The bone implant of claim 1, wherein said intermediate member
is rotatably attached within the tubular body, the intermediate
member including a threaded stem that is threaded into a threaded
bore of said distal end of the tubular body.
17. The bone implant of claim 1, wherein the implant is an
expandable implant, the intermediate member including a threaded
stem close to the distal end of the tubular body and the distal end
of the tubular body includes a plurality of longitudinal cuts
defining an expandable portion that is capable of being radially
outwardly expanded by an expanding nut that is threadably mounted
on the stem and longitudinally moves along the stem under rotation
of the intermediate member, said nut being retained against
rotation in said distal end of the tubular body but permitted to
slide along said stem of the intermediate member.
18. The bone implant of claim 17, wherein the expanding nut has a
truncate pyramid shape with its vertexes in said longitudinal cuts
of the tubular body.
19. A bone implant comprising a fixing tubular body for fixing in
the bone, the tubular body including a distal end for being affixed
within a bone bore and a proximal end for remaining accessible
outside the bone and a prosthesis piece being received in the
proximal end, the bone implant comprising:
a mounting intermediate member for mounting said prosthesis piece,
the intermediate member being removably mounted within said tubular
body,
the intermediate member including a proximal end in communication
with an inner surface for receiving a fixing stud of said
prosthesis piece;
said proximal end of the fixing tubular body and said proximal end
of the intermediate member have corresponding coupling plates with
one plate abutted against the other; and
wherein the plate of the intermediate mounting member includes a
radially extended notch for receiving a screwdriver for rotating
the intermediate member, said notch passing through the plate of
the intermediate member.
20. A bone implant comprising a fixing tubular body for fixing in
the bone, the tubular body including a distal end for being affixed
within a bone bore and a proximal end for remaining accessible
outside the bone and a prosthesis piece being received in the
proximal end, the bone implant comprising:
a mounting intermediate member for mounting said prosthesis piece,
the intermediate member being removably mounted within said tubular
body,
the intermediate member including a proximal end in communication
with an inner surface for receiving a fixing stud of said
prosthesis piece; and
wherein said intermediate member is rotatably attached within the
tubular body, said inner surface of the intermediate member being
threaded and receives a fixing stem having a proximal end threaded
in said threaded inner surface and a distal end having a retention
head arranged in said distal end of the tubular body.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a bone implant, preferably a bone
implant for implanting prosthetic pieces in a bone, such as dental
prosthesis in a jaw, the implant comprising a fixing piece or body
to be affixed in a bone and a mounting intermediate member for
receiving the prosthesis piece, the mounting member being capable
of being removed without traumatic effects for the patient in the
event that the prosthesis or a fixing stud thereof is broken. The
intermediate member can be removed even after a long time with the
fixing body already integrated into the bone. Of course, the
concepts of the invention are easily applied to any implant piece
that must be implanted in a human being or animal bone. In
addition, the invention is not only applied to expandable implants,
of the type that can be initially expanded to get a retention into
the bone, but also to non expandable implants.
2. Description of the Prior Art
It is well known in medical art to provide bone implants that are
useful for affixing a prosthetic piece in a bone, in replacement of
any lacking natural piece or member or for joining parts of one or
more bones. More, particularly, these implants are well known in
odontology wherein dental implants are used for replacing a dental
piece that has been lost or extracted either in a human or animal
patient. One of the problems or traumatic drawbacks of implanting a
dental prosthesis in a patient is that a long time is necessary to
assure to the patient that the implant is entirely or totally
integrated to the jaw of the patient. Generally, after the
extraction or loss of the dental piece, a fixing body of the
implant is inserted and implanted into the jaw and several months
must be awaited to determine whether the fixing body has been
integrated to the bone or bone fibers of the bore in the jaw, this
determination being necessary to continue or not with the next step
of affixing the prosthetic piece into the implant. If the body has
not been integrated the same must be replaced and a new waiting
period begins again. This provokes anxiety and affliction in the
patient who must await for months before receiving a positive
diagnostic from the odontologist or the implantologist and upon a
negative diagnostic the patient knows that the fixing body must be
removed and that several additional months must be awaited again.
With the purpose of shortening this waiting periods some implants,
either of the expandable or non expandable type have been
developed. The expandable implants are based in the theory that
greater pressure against the bone generates greater bone growth.
These implants are installed within the bone orifice or bore
resulting from the loosen or removed dental piece or within a bore
made in the bone and the implant is radially expanded in order to
get a positive initial pressure and retention. During the first
weeks from the installation it is possible to verify whether
micro-mobility exists and, if the micro-mobility is detected the
implant is additionally expanded to improve the radial retention.
The purpose of these additional expansions is to get the immobility
of the fixing piece that is a fundamental condition to reach the
integration of the piece into the bone. While these implants have
been improved insofar as the micro mobility is concerned, the same
have not taken into account an important aspect of the implants,
that is the need of replacing a broken prosthesis after a long time
from the integration of the implant into the bone.
Generally, prosthetic dental pieces are affixed to a fixation stud
or abutment that is installed by threading or adhesive within the
fixing or mounting body that is already integrated into the bone.
During the use of the prosthetic piece, if the fixing stud is
broken within the fixing body that is already integrated or
implanted, the broken portion of the stud that remains within the
implanted body must be removed before a new prosthetic piece is
re-installed. Any professional skilled in the art knows that the
removal of this broken stud in the small room of the patient's
mouth is very difficult if not impossible. Said broken portion is
not accessible and very frequently the portion cannot be extracted,
therefore the implant body must be removed from its implantation by
drilling the patient's jaw to release the fixing body from the jaw
bone, which is very traumatic for the patient.
The initial fixation of the implant has been treated by several
professionals and disclosed in many documents like the U.S. Pat.
Nos. 5,004,421 and 5,087,199 to Lazarof, which disclose expandable
implants having a fixing piece that is introduced and threaded into
a patient's bone and has a hollow interior that is also threaded
and a plurality of longitudinal cuts in the implant body. An
expanding piece is arranged within the hollow interior, the piece
being accessed from a top end of the fixing body by means of a tool
that is introduced within the implant body to cause the expanding
piece to rotate and move upwardly in order to expand the implant
body to enhance the retention thereof into the bone. An upper
portion of the fixation body has a threaded inner orifice for
receiving a fixing stud or abutment of the dental prosthesis. While
a better initial fixation is achieved no consideration is made to
the event that the prosthesis stud is broken and the prosthesis is
loosened.
U.S. Pat. No. 5,489,210 discloses a dental implant having a
fixation body that is introduced within the body and has a
plurality of longitudinal cuts at a lower end of the body, this
lower end being expanded by an expanding piece that is introduced
through an upper end into the implant body and exerts a pressure
against the lower end of the body to outwardly radially expand the
same against the bone. Again, the initial pressure of the implant
against the bone is improved but a solution to the event of a
broken stud is neither provided nor suggested. The stud of the
prosthetic piece is mounted directly within the fixing body of the
implant.
U.S. Pat. No. 5,611,688 discloses an expandable dental implant also
comprising a hollow tubular outer body that is affixed by expansion
into the bone, the expansion being obtained by an expanding screw
that is inserted into the hollow body and the initial fixation of
the implant is improved. This patent does not disclose any solution
to the event that the prosthesis and its fixing stud are loosen or
broken. In like manner, U.S. Pat. No. 5,931,674 discloses an
expandable implant very similar to the '688 patent, but no means
for permitting an easy removal of a broken fixing stud are
provided, and the problem is not addressed.
It would be therefore convenient to have a new expandable or non
expandable implant provided with means for enhancing the initial
fixation of the implant within the bone and means for permitting
the easy removal of the fixation stud of the prosthesis piece in
the event the stud is broken with a portion of the stud remaining
within an implant body already integrated to the bone.
SUMMARY OF THE INVENTION
It is therefore one object of the present invention to provide a
bone implant for fixing a dental prosthesis into a bone, the
prosthesis being fixed into an implant body by means of a fixing
stud that is fixed into the body, in the event the stud is broken
and the prosthesis is loosened the novel implant permitting the
easy removal of a portion of the stud that remains within the body
without the need of removing the body from the bone.
It is still another object of the present invention to provide a
bone implant comprising a fixing tubular body for fixing in the
bone, the tubular body including a distal end for being affixed
within a bone bore and a proximal end for remaining accessible
outside the bone and a prosthesis piece being received in the
proximal end, the bone implant comprising a mounting intermediate
member for mounting said prosthesis piece, the intermediate member
being removably mounted within said tubular body, the intermediate
member including a proximal end in communication with an inner
surface for receiving a fixing stud of said prosthesis piece.
It is a further object of the present invention to provide a bone
implant comprising a fixing tubular body for fixing in the bone,
the tubular body including a distal end for being affixed within a
bone bore and a proximal end for remaining accessible outside the
bone and within the gum and for receiving a prosthesis piece, the
distal end of the body including a plurality of longitudinal cuts
that permit a lower portion of the body be radially outwardly
expanded by an expanding member that is received within said body,
said expanding member being fixed to a distal end of a stem having
a proximal end within said tubular body and a threaded outer
surface, the implant also comprising a rotatable mounting
intermediate member that includes a threaded inner surface within
which said stem is threadably received, the mounting intermediate
member including an upper end receiving the prosthesis piece.
The above and other objects, features and advantages of this
invention will be better understood when taken in connection with
the accompanying drawings and description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is illustrated by way of example in the
following drawings wherein:
FIG. 1 shows a partially cross-sectional, elevation view of an
expandable implant according to a preferred embodiment of the
invention;
FIG. 2 shows a cross-sectional, perspective view of the mounting
intermediate member of FIG. 1;
FIG. 3 shows a plant, bottom view of the implant of FIG. 1;
FIG. 4 shows a cross-sectional elevation view of the implant of
FIG. 1 once expanded by the expanding member;
FIG. 5 shows a partial cross-sectional view of a proximal end of
the implant of FIG. 1;
FIG. 6 shows a partially cross-sectional, elevation view of a non
expandable implant according to another preferred embodiment of the
invention;
FIG. 7 shows a plant, bottom view of the implant of FIG. 6;
FIG. 8 shows a partial cross-sectional view of a proximal end of
the implant according to another embodiment of the invention;
FIG. 9 shows a partially cross-sectional, elevation view of an
expandable implant according to another preferred embodiment of the
invention; and
FIG. 10 shows a partially cross-sectional, elevation view of a non
expandable implant according to another preferred embodiment of the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now referring in detail to the drawings it may be seen from FIGS.
1-5 an expandable bone implant according to the invention that is
identified by reference number 1 and comprises a fixation or fixing
tubular body 2 having a distal end 3 and a proximal end 4
terminating in a coupling plate or coupling end 5 having a first
cylindrical portion 6 and a second upper conical portion 7. The
distal end is adapted to be introduced and remain within a bone 8
and more particularly within a bore or orifice 9 that can be made
artificially in the bone or corresponds to the natural orifice
resulting from the extraction or loosening of a natural tooth.
When the invention is applied to an expandable implant, distal end
3 includes a plurality of longitudinal cuts 10, preferably four
cuts 10. These cuts define corresponding flexible portions or
deformable tongues 11 that may be slightly tapered to facilitate
the initial insertion of body 2 within orifice 9. Tongues 11 will
be provided with the necessary elasticity for radially outwardly
expanding as it will be further explained. The outer surface of
body 2 may be smooth and plain or may be treated to enhance its
adherence and obtain an improved body-bone integration. Thus, the
surface may be treated and/or coated with hydroxyapatite, titanium
plasma spray or acids. Depending on the bone hardness, for example,
the body surface would be treated or coated, in less dense bone
rough, the titanium plasma spray (TPS) and the hydroxyapatite (HA)
coatings help as well by presenting maximal interfacial areas. The
outer surface of body 2 may be provided with threads, notches, and
indentations, and may be screw machined, acid etched, machined
roughened, stepped, and combined with the above coatings. As an
example, threads 12 are illustrated only at the right side in FIGS.
1, 4, 5, 6, 8-10, but, as it will be apparent to any person skilled
in the art, threads 12, if provided, may extend all around the body
or along a partial circumference around the body. Threads 12 may
have any cross-section and configuration, preferably for obtaining
a better grip between the fixation body and bone 8 to get a more
stable retention.
Proximal end 4 and more particularly mounting plate 5 remain
outside bone 8 and are adapted to receive a dental prosthetic piece
13, schematically illustrated in FIGS. 1, 4 and 6.
Body 2 is hollow and tubular and defines a bore 14 extending along
the body and receiving an expanding member 15 having a stem 16 that
is threaded along at least a part of the length thereof. While bore
14 is illustrated as being a stepped bore, the bore may be smooth,
plain or straight cylindrical from one end to the opposite end.
Expanding member 15 has a truncated pyramid configuration with
sloped walls 17 of member 15 resting against tongues 11 of body 2
and corners 18 of the truncated pyramid are accommodated within
longitudinal cuts 10, whereby any rotation of expanding member 15
is prevented by the locking or wedging effect between member 15 and
cuts 10 and tongues 11.
A mounting intermediate member 19 is inserted through proximal end
4, member 19 including, at its proximal end, a coupling plate 20
capable of entering in a mating relationship with the plate or
coupling end 5. Plate 20 rests and abuts against end 5. Member 19
has an outer surface, preferably a smooth outer surface, adapted to
be accommodated within body 2 and has a threaded interior 21 that
receives threaded stem 16 of expanding member or head 15. With this
assembly, by rotating intermediate member 19, either in clockwise
or counterclockwise direction, a corresponding upward or downward
sliding movement of member 15 and stem will be obtained because
stem 16 is threadably connected to member 19 along threads 21 and
member 15 is prevented from rotating within tongues 11. Upper plate
20 of member 19 is provided with a notch 22 radially extending
across the plate and passing through the plate, adapted to receive
the tip of a screwdriver for rotating the intermediate member. In
like manner, coupling plate 5 is provided with a groove 23
extending radially across end 4 of body 2 and within end 4 along a
small depth that is to be covered by prosthesis 13. By rotating
intermediate member 19 notch 22 and groove 23 are capable of being
placed in mating relationship in order that the tip of a
screwdriver may be inserted simultaneously into both the notch and
the groove.
During the operation of installing or mounting the implant within
bore 9 of bone 8 the implant is arranged with its components
assembled as it is shown in FIG. 1, that is member 15 is within
distal end 3 with tongues 11 in a non expanded condition. Once the
implant is introduced into bore 9 as shown in FIG. 1 a tool, such
as a screwdriver, is introduced into notch 22 and it is rotated
until notch 22 is aligned with groove 23, see FIG. 5. With notch 22
and groove 23 in this aligned position, the tip of the screwdriver
will be not only within notch 22 but also within groove 23,
therefore the screwdriver may be rotated in order to rotate all the
implant assembly to facilitate the introduction thereof into bore
9. If threads 12 are provided according to an embodiment of the
invention, threads 12 will penetrate the bone walls like in a screw
and an initial retention of the implant within the bone will be
obtained. If threads 12 are not provided the rotation of implant 1
will facilitate in any case the insertion thereof into the
bore.
Once the implant has been installed as shown in FIG. 1, the
screwdriver is moved slightly upwardly enough to remove the
screwdriver tip from groove 23 but retaining the tip into notch 22.
Then, the screwdriver is rotated to cause the rotation of
intermediate member 19 in such a way to cause the upward movement
of stem 16 along thread 21. This upward movement will cause walls
17 of expanding member 15 to exert a radial expanding pressure
against tongues 11 and to cause tongues 11 to radially expand
against the wall of bore 9 as indicated by the arrows in FIG. 4.
Intermediate member would be rotated until a desired retention is
achieved between the outer surface of body 2, either with or
without threads 12, and the bone.
Prosthesis piece 13 is attached or affixed into intermediate member
19 by means of a fixing pin or stud 24 of an abutment 25, which pin
or stud may be smooth or threaded, or partially smooth and
partially threaded. The stud/abutment assembly may be only one
integral piece or may comprise two or more parts, with a
configuration either straight cylindrical or conical, as well as
perpendicular or inclined. Depending on whether stud 24 is
threaded, as shown in FIG. 4, or smooth (not illustrated), the stud
will be threadably retained in corresponding threads 21 of member
19 or retained by adhesive or cement into at least a smooth portion
of an inner surface of member 19. All this assembly is covered by
prosthesis 13 that extends into gum 26 indicated by a phantom line
passing through the prosthesis in FIGS. 1 and 4.
In the event prosthesis 13 is loosened, for example because the
stud is broken, which is a frequent accident resulting from the
high forces involved in chewing, a new prosthesis must be prepared
and installed in the implant. It is to be remarked that when this
accident occurs fixing body 2 is already osseous-integrated, that
is integrated with the surrounding bone because of the bone growth
around and into the parts of the implant. As stated above, the
removal of the portion of stud that remains broken in the implant
is almost impossible to be carried out and the removal of the
entire implant is frequently necessary. According to the invention,
if stud is broken within intermediate member 19 and a portion of
the stud remains within member 19, the removal of the stud is
possible thank to the possibility of removing member 19 by removing
the same from body 2. The removal of member 19 is carried out by
unscrewing the same either from stem 16, FIGS. 1, 4, 6, or from
threads 31 shown in FIG. 8, by using a simple screwdriver or any
other proper tool that is inserted into notch 22 only. This removal
is possible even with body 2 and member 15/stem 16 are already
integrated to the bone, that is completely surrounded and retained
by the bone. By unscrewing, member 19 is upwardly removed in order
to allow the implantologist to repair the prosthesis by easily
removing the broken portion of the stud from member 19 or to
install a new intermediate member containing a new prosthesis and
stud. This is a remarkable improvement as compared to the prior art
because the traumatic removal of the fixing body already integrated
to the bone is avoided for the benefit of the patient's comfort and
the implantologist's practice.
While the concepts of the invention have been illustrated and
disclosed in relation to an implant of the expandable type, as
illustrated in FIGS. 1-5, it must be understood that the invention
is likewise applicable to non-expandable implants such as the one
illustrated in FIGS. 6 and 7.
As shown in FIGS. 6, 7, the equivalent components of the invention
are identified in these Figures with the same reference numbers of
FIGS. 1-5. Thus, intermediate member 19 may be like any of the ones
illustrated in FIGS. 1-5, but fixation body 2 of FIGS. 6, 7,
differing from body 2 of FIGS. 1-5, has a distal end 3 without cuts
10, that is the body is entirely cylindrical therefore, without
expansion capability. Instead of an expanding member 15, a simple
screw 27 is provided, the screw having a conventional head 28
provided with an actuating groove 29 for receiving the tip of a
screwdriver to rotate the screw and screw the same into
intermediate member 19 upon assembling the implant before
installing the same into bore 9. The purpose of screw 27 is to
retain intermediate member 19 within fixation body 2. After the
osseous-integration of body 2 has been completed, if the prosthesis
stud (not illustrated in FIG. 6) is broken, intermediate member 19
may be easily removed by unscrewing the same by means of a
screwdriver, for example.
According to another alternative embodiment of the invention, the
outer surface of intermediate member 19 has threads 30, along a
total or partial length of the member, and bore 14 inside body 2 is
provided with threads 31 extending along the entire or partial
length of the bore, whereby intermediate member 19 may be
threadably and removably mounted within body 2 without the need of
any additional screw 27 of FIG. 8. Inner threads 21 and threads 30,
31 and 12 preferably have the same helical sense to prevent member
19 from loosening from body 2, or body from loosening from bore 9,
when stud 24 is being screwed into intermediate member 19. Member
19 may define, at its proximal end, a head or plate 32 provided
with a groove for receiving a screwdriver, or the head or plate may
have a polygonal configuration, quadrangular, hexagonal, for
connecting a wrench, for example.
FIG. 9 shows an expandable bone implant according to another
alternative embodiment of the invention wherein the expanding
member 15 of FIG. 1 consists of an expanding nut 33 also having
sloped walls 17, and threaded stem 16 of FIG. 1 is replaced by stem
35 not joined to the expanding member but to the intermediate
member now indicated with reference number 34. Similarly to the
assembly of FIG. 1, by rotating intermediate member 34, either in
clockwise or counterclockwise direction, a corresponding upward or
downward sliding movement of member 33 along stem 35 will be
obtained because stem 35 is threadably connected to nut 33 which is
prevented from rotating within tongues 11. Stem 35 may be an
integral part of intermediate member 34 or may be joined by any
proper manner like welding, etc.
According to another alternative embodiment FIG. 10 shows a non
expandable implant similar to implant of FIG. 6, wherein a threaded
stem 35/intermediate member 34 like the assembly shown in FIG. 9
has been used to replace screw 27/head 28. Since this is a non
expandable implant no expanding member is provided and, instead,
body 2 is provided with a threaded bottom bore 36 at bottom end 3.
Like the above embodiments, member 34 has an inner surface that may
be entirely or partially threaded as shown in FIGS. 9, 10, and stud
24 may be, accordingly, a threaded or a smooth stud or a partial
threaded and a partial smooth stud.
As it is well clear for any expert in the art, if the abutment or
stud of a prosthesis is broken with a portion of the broken stud
remaining within intermediate member 19, 34, the stud portion,
together with the intermediate member, may be easily removed from
the fixation body for repairing the prosthesis and installing a new
one.
While preferred embodiments of the present invention have been
illustrated and described, it will be obvious to those skilled in
the art that various changes and modifications may be made therein
without departing from the scope of the invention as defined in the
appended claims.
* * * * *